When you install a new version of ChefDK and try to run Test Kitchen the following error message may appear
!!!!!! The `berkshelf' gem is missing and must be installed or cannot be properly activated. Run `gem install berkshelf` or add the following to your Gemfile if you are using Bundler: `gem 'berkshelf'`.
To reinstall Brekshelf in the correct version of Ruby execute
gem install berkshelf